20212121321 has 32 divisors (see below), whose sum is σ = 25791932160. Its totient is φ = 15419621376.

The previous prime is 20212121297. The next prime is 20212121339. The reversal of 20212121321 is 12312121202.

It is a cyclic number.

It is not a de Polignac number, because 20212121321 - 2¹⁴ = 20212104937 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a self number, because there is not a number n which added to its sum of digits gives 20212121321.

It is not an unprimeable number, because it can be changed into a prime (20212121381) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1296851 + ... + 1312343.

It is an arithmetic number, because the mean of its divisors is an integer number (805997880).

Almost surely, 2^20212121321 is an apocalyptic number.

It is an amenable number.

20212121321 is a deficient number, since it is larger than the sum of its proper divisors (5579810839).

20212121321 is a wasteful number, since it uses less digits than its factorization.

20212121321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16113.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 20212121321 its reverse (12312121202), we get a palindrome (32524242523).

The spelling of 20212121321 in words is "twenty billion, two hundred twelve million, one hundred twenty-one thousand, three hundred twenty-one".